annotate hotspot/src/share/vm/utilities/hashtable.cpp @ 36384:b0b41336a9a8

8143226: Minor updates to Event Based tracing Reviewed-by: jbachorik, egahlin
author mgronlun
date Tue, 01 Mar 2016 23:46:09 +0100
parents 392b50de06c6
children 2b65f4db449e
rev   line source
duke@1 1 /*
goetz@35498 2 * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved.
duke@1 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@1 4 *
duke@1 5 * This code is free software; you can redistribute it and/or modify it
duke@1 6 * under the terms of the GNU General Public License version 2 only, as
duke@1 7 * published by the Free Software Foundation.
duke@1 8 *
duke@1 9 * This code is distributed in the hope that it will be useful, but WITHOUT
duke@1 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@1 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@1 12 * version 2 for more details (a copy is included in the LICENSE file that
duke@1 13 * accompanied this code).
duke@1 14 *
duke@1 15 * You should have received a copy of the GNU General Public License version
duke@1 16 * 2 along with this work; if not, write to the Free Software Foundation,
duke@1 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@1 18 *
trims@5547 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@5547 20 * or visit www.oracle.com if you need additional information or have any
trims@5547 21 * questions.
duke@1 22 *
duke@1 23 */
duke@1 24
stefank@7397 25 #include "precompiled.hpp"
coleenp@13199 26 #include "classfile/altHashing.hpp"
goetz@35498 27 #include "classfile/javaClasses.inline.hpp"
gziemski@24426 28 #include "classfile/stringTable.hpp"
stefank@7397 29 #include "memory/allocation.inline.hpp"
coleenp@13097 30 #include "memory/filemap.hpp"
stefank@7397 31 #include "memory/resourceArea.hpp"
stefank@7397 32 #include "oops/oop.inline.hpp"
stefank@7397 33 #include "runtime/safepoint.hpp"
stefank@7397 34 #include "utilities/dtrace.hpp"
stefank@7397 35 #include "utilities/hashtable.hpp"
stefank@7397 36 #include "utilities/hashtable.inline.hpp"
iklam@17610 37 #include "utilities/numberSeq.hpp"
duke@1 38
coleenp@8076 39
mgerdin@26421 40 // This hashtable is implemented as an open hash table with a fixed number of buckets.
duke@1 41
mgerdin@26421 42 template <MEMFLAGS F> BasicHashtableEntry<F>* BasicHashtable<F>::new_entry_free_list() {
mgerdin@26421 43 BasicHashtableEntry<F>* entry = NULL;
mgerdin@26421 44 if (_free_list != NULL) {
duke@1 45 entry = _free_list;
duke@1 46 _free_list = _free_list->next();
mgerdin@26421 47 }
mgerdin@26421 48 return entry;
mgerdin@26421 49 }
mgerdin@26421 50
mgerdin@26421 51 // HashtableEntrys are allocated in blocks to reduce the space overhead.
mgerdin@26421 52 template <MEMFLAGS F> BasicHashtableEntry<F>* BasicHashtable<F>::new_entry(unsigned int hashValue) {
mgerdin@26421 53 BasicHashtableEntry<F>* entry = new_entry_free_list();
mgerdin@26421 54
mgerdin@26421 55 if (entry == NULL) {
jrose@1551 56 if (_first_free_entry + _entry_size >= _end_block) {
jrose@1551 57 int block_size = MIN2(512, MAX2((int)_table_size / 2, (int)_number_of_entries));
duke@1 58 int len = _entry_size * block_size;
jrose@1551 59 len = 1 << log2_intptr(len); // round down to power of 2
jrose@1551 60 assert(len >= _entry_size, "");
zgu@13195 61 _first_free_entry = NEW_C_HEAP_ARRAY2(char, len, F, CURRENT_PC);
duke@1 62 _end_block = _first_free_entry + len;
duke@1 63 }
zgu@13195 64 entry = (BasicHashtableEntry<F>*)_first_free_entry;
duke@1 65 _first_free_entry += _entry_size;
duke@1 66 }
duke@1 67
jrose@1551 68 assert(_entry_size % HeapWordSize == 0, "");
duke@1 69 entry->set_hash(hashValue);
duke@1 70 return entry;
duke@1 71 }
duke@1 72
duke@1 73
zgu@13195 74 template <class T, MEMFLAGS F> HashtableEntry<T, F>* Hashtable<T, F>::new_entry(unsigned int hashValue, T obj) {
zgu@13195 75 HashtableEntry<T, F>* entry;
duke@1 76
zgu@13195 77 entry = (HashtableEntry<T, F>*)BasicHashtable<F>::new_entry(hashValue);
coleenp@8076 78 entry->set_literal(obj);
duke@1 79 return entry;
duke@1 80 }
duke@1 81
coleenp@13087 82 // Check to see if the hashtable is unbalanced. The caller set a flag to
coleenp@13087 83 // rehash at the next safepoint. If this bucket is 60 times greater than the
coleenp@13087 84 // expected average bucket length, it's an unbalanced hashtable.
coleenp@13087 85 // This is somewhat an arbitrary heuristic but if one bucket gets to
coleenp@13087 86 // rehash_count which is currently 100, there's probably something wrong.
coleenp@13087 87
mgerdin@26421 88 template <class T, MEMFLAGS F> bool RehashableHashtable<T, F>::check_rehash_table(int count) {
mgerdin@26421 89 assert(this->table_size() != 0, "underflow");
mgerdin@26421 90 if (count > (((double)this->number_of_entries()/(double)this->table_size())*rehash_multiple)) {
coleenp@13087 91 // Set a flag for the next safepoint, which should be at some guaranteed
coleenp@13087 92 // safepoint interval.
coleenp@13087 93 return true;
coleenp@13087 94 }
coleenp@13087 95 return false;
coleenp@13087 96 }
coleenp@13087 97
mgerdin@26421 98 template <class T, MEMFLAGS F> juint RehashableHashtable<T, F>::_seed = 0;
coleenp@13199 99
coleenp@13087 100 // Create a new table and using alternate hash code, populate the new table
coleenp@13087 101 // with the existing elements. This can be used to change the hash code
coleenp@13087 102 // and could in the future change the size of the table.
coleenp@13087 103
mgerdin@26421 104 template <class T, MEMFLAGS F> void RehashableHashtable<T, F>::move_to(RehashableHashtable<T, F>* new_table) {
coleenp@13199 105
coleenp@13199 106 // Initialize the global seed for hashing.
coleenp@13199 107 _seed = AltHashing::compute_seed();
coleenp@13199 108 assert(seed() != 0, "shouldn't be zero");
coleenp@13199 109
coleenp@13199 110 int saved_entry_count = this->number_of_entries();
coleenp@13087 111
coleenp@13087 112 // Iterate through the table and create a new entry for the new table
coleenp@13087 113 for (int i = 0; i < new_table->table_size(); ++i) {
mgerdin@26421 114 for (HashtableEntry<T, F>* p = this->bucket(i); p != NULL; ) {
zgu@13195 115 HashtableEntry<T, F>* next = p->next();
coleenp@13087 116 T string = p->literal();
coleenp@13087 117 // Use alternate hashing algorithm on the symbol in the first table
coleenp@13728 118 unsigned int hashValue = string->new_hash(seed());
coleenp@13087 119 // Get a new index relative to the new table (can also change size)
coleenp@13087 120 int index = new_table->hash_to_index(hashValue);
coleenp@13087 121 p->set_hash(hashValue);
coleenp@13097 122 // Keep the shared bit in the Hashtable entry to indicate that this entry
coleenp@13097 123 // can't be deleted. The shared bit is the LSB in the _next field so
coleenp@13097 124 // walking the hashtable past these entries requires
coleenp@13097 125 // BasicHashtableEntry::make_ptr() call.
coleenp@13097 126 bool keep_shared = p->is_shared();
andrew@13342 127 this->unlink_entry(p);
coleenp@13087 128 new_table->add_entry(index, p);
coleenp@13097 129 if (keep_shared) {
coleenp@13097 130 p->set_shared();
coleenp@13097 131 }
coleenp@13087 132 p = next;
coleenp@13087 133 }
coleenp@13087 134 }
coleenp@13087 135 // give the new table the free list as well
coleenp@13087 136 new_table->copy_freelist(this);
coleenp@13087 137 assert(new_table->number_of_entries() == saved_entry_count, "lost entry on dictionary copy?");
coleenp@13087 138
coleenp@13087 139 // Destroy memory used by the buckets in the hashtable. The memory
coleenp@13087 140 // for the elements has been used in a new table and is not
coleenp@13087 141 // destroyed. The memory reuse will benefit resizing the SystemDictionary
coleenp@13087 142 // to avoid a memory allocation spike at safepoint.
zgu@13195 143 BasicHashtable<F>::free_buckets();
coleenp@13087 144 }
coleenp@13087 145
zgu@13195 146 template <MEMFLAGS F> void BasicHashtable<F>::free_buckets() {
coleenp@13097 147 if (NULL != _buckets) {
coleenp@13097 148 // Don't delete the buckets in the shared space. They aren't
coleenp@13097 149 // allocated by os::malloc
coleenp@13097 150 if (!UseSharedSpaces ||
coleenp@13097 151 !FileMapInfo::current_info()->is_in_shared_space(_buckets)) {
coleenp@27880 152 FREE_C_HEAP_ARRAY(HashtableBucket, _buckets);
coleenp@13097 153 }
coleenp@13097 154 _buckets = NULL;
coleenp@13097 155 }
coleenp@13097 156 }
coleenp@13097 157
coleenp@13097 158
duke@1 159 // Reverse the order of elements in the hash buckets.
duke@1 160
zgu@13195 161 template <MEMFLAGS F> void BasicHashtable<F>::reverse() {
duke@1 162
duke@1 163 for (int i = 0; i < _table_size; ++i) {
zgu@13195 164 BasicHashtableEntry<F>* new_list = NULL;
zgu@13195 165 BasicHashtableEntry<F>* p = bucket(i);
duke@1 166 while (p != NULL) {
zgu@13195 167 BasicHashtableEntry<F>* next = p->next();
duke@1 168 p->set_next(new_list);
duke@1 169 new_list = p;
duke@1 170 p = next;
duke@1 171 }
duke@1 172 *bucket_addr(i) = new_list;
duke@1 173 }
duke@1 174 }
duke@1 175
duke@1 176
duke@1 177 // Copy the table to the shared space.
duke@1 178
zgu@13195 179 template <MEMFLAGS F> void BasicHashtable<F>::copy_table(char** top, char* end) {
duke@1 180
duke@1 181 // Dump the hash table entries.
duke@1 182
duke@1 183 intptr_t *plen = (intptr_t*)(*top);
duke@1 184 *top += sizeof(*plen);
duke@1 185
duke@1 186 int i;
duke@1 187 for (i = 0; i < _table_size; ++i) {
zgu@13195 188 for (BasicHashtableEntry<F>** p = _buckets[i].entry_addr();
duke@1 189 *p != NULL;
duke@1 190 p = (*p)->next_addr()) {
duke@1 191 if (*top + entry_size() > end) {
coleenp@8076 192 report_out_of_shared_space(SharedMiscData);
duke@1 193 }
zgu@13195 194 *p = (BasicHashtableEntry<F>*)memcpy(*top, *p, entry_size());
duke@1 195 *top += entry_size();
duke@1 196 }
duke@1 197 }
duke@1 198 *plen = (char*)(*top) - (char*)plen - sizeof(*plen);
duke@1 199
duke@1 200 // Set the shared bit.
duke@1 201
duke@1 202 for (i = 0; i < _table_size; ++i) {
zgu@13195 203 for (BasicHashtableEntry<F>* p = bucket(i); p != NULL; p = p->next()) {
duke@1 204 p->set_shared();
duke@1 205 }
duke@1 206 }
duke@1 207 }
duke@1 208
duke@1 209
duke@1 210
duke@1 211 // Reverse the order of elements in the hash buckets.
duke@1 212
zgu@13195 213 template <class T, MEMFLAGS F> void Hashtable<T, F>::reverse(void* boundary) {
duke@1 214
zgu@13195 215 for (int i = 0; i < this->table_size(); ++i) {
zgu@13195 216 HashtableEntry<T, F>* high_list = NULL;
zgu@13195 217 HashtableEntry<T, F>* low_list = NULL;
zgu@13195 218 HashtableEntry<T, F>* last_low_entry = NULL;
zgu@13195 219 HashtableEntry<T, F>* p = bucket(i);
duke@1 220 while (p != NULL) {
zgu@13195 221 HashtableEntry<T, F>* next = p->next();
duke@1 222 if ((void*)p->literal() >= boundary) {
duke@1 223 p->set_next(high_list);
duke@1 224 high_list = p;
duke@1 225 } else {
duke@1 226 p->set_next(low_list);
duke@1 227 low_list = p;
duke@1 228 if (last_low_entry == NULL) {
duke@1 229 last_low_entry = p;
duke@1 230 }
duke@1 231 }
duke@1 232 p = next;
duke@1 233 }
duke@1 234 if (low_list != NULL) {
duke@1 235 *bucket_addr(i) = low_list;
duke@1 236 last_low_entry->set_next(high_list);
duke@1 237 } else {
duke@1 238 *bucket_addr(i) = high_list;
duke@1 239 }
duke@1 240 }
duke@1 241 }
duke@1 242
mgerdin@26421 243 template <class T, MEMFLAGS F> int RehashableHashtable<T, F>::literal_size(Symbol *symbol) {
iklam@17610 244 return symbol->size() * HeapWordSize;
iklam@17610 245 }
iklam@17610 246
mgerdin@26421 247 template <class T, MEMFLAGS F> int RehashableHashtable<T, F>::literal_size(oop oop) {
iklam@17610 248 // NOTE: this would over-count if (pre-JDK8) java_lang_Class::has_offset_field() is true,
iklam@17610 249 // and the String.value array is shared by several Strings. However, starting from JDK8,
iklam@17610 250 // the String.value array is not shared anymore.
iklam@17610 251 assert(oop != NULL && oop->klass() == SystemDictionary::String_klass(), "only strings are supported");
iklam@17610 252 return (oop->size() + java_lang_String::value(oop)->size()) * HeapWordSize;
iklam@17610 253 }
iklam@17610 254
iklam@17610 255 // Dump footprint and bucket length statistics
iklam@17610 256 //
iklam@17610 257 // Note: if you create a new subclass of Hashtable<MyNewType, F>, you will need to
iklam@17610 258 // add a new function Hashtable<T, F>::literal_size(MyNewType lit)
iklam@17610 259
mgerdin@26421 260 template <class T, MEMFLAGS F> void RehashableHashtable<T, F>::dump_table(outputStream* st, const char *table_name) {
iklam@17610 261 NumberSeq summary;
iklam@17610 262 int literal_bytes = 0;
iklam@17610 263 for (int i = 0; i < this->table_size(); ++i) {
iklam@17610 264 int count = 0;
mgerdin@26421 265 for (HashtableEntry<T, F>* e = this->bucket(i);
iklam@17610 266 e != NULL; e = e->next()) {
iklam@17610 267 count++;
iklam@17610 268 literal_bytes += literal_size(e->literal());
iklam@17610 269 }
iklam@17610 270 summary.add((double)count);
iklam@17610 271 }
iklam@17610 272 double num_buckets = summary.num();
iklam@17610 273 double num_entries = summary.sum();
iklam@17610 274
mgerdin@26421 275 int bucket_bytes = (int)num_buckets * sizeof(HashtableBucket<F>);
iklam@17610 276 int entry_bytes = (int)num_entries * sizeof(HashtableEntry<T, F>);
iklam@17610 277 int total_bytes = literal_bytes + bucket_bytes + entry_bytes;
iklam@17610 278
iklam@17610 279 double bucket_avg = (num_buckets <= 0) ? 0 : (bucket_bytes / num_buckets);
iklam@17610 280 double entry_avg = (num_entries <= 0) ? 0 : (entry_bytes / num_entries);
iklam@17610 281 double literal_avg = (num_entries <= 0) ? 0 : (literal_bytes / num_entries);
iklam@17610 282
iklam@17610 283 st->print_cr("%s statistics:", table_name);
iklam@17610 284 st->print_cr("Number of buckets : %9d = %9d bytes, avg %7.3f", (int)num_buckets, bucket_bytes, bucket_avg);
iklam@17610 285 st->print_cr("Number of entries : %9d = %9d bytes, avg %7.3f", (int)num_entries, entry_bytes, entry_avg);
iklam@17610 286 st->print_cr("Number of literals : %9d = %9d bytes, avg %7.3f", (int)num_entries, literal_bytes, literal_avg);
iklam@17610 287 st->print_cr("Total footprint : %9s = %9d bytes", "", total_bytes);
iklam@17610 288 st->print_cr("Average bucket size : %9.3f", summary.avg());
iklam@17610 289 st->print_cr("Variance of bucket size : %9.3f", summary.variance());
iklam@17610 290 st->print_cr("Std. dev. of bucket size: %9.3f", summary.sd());
iklam@17610 291 st->print_cr("Maximum bucket size : %9d", (int)summary.maximum());
iklam@17610 292 }
iklam@17610 293
duke@1 294
duke@1 295 // Dump the hash table buckets.
duke@1 296
zgu@13195 297 template <MEMFLAGS F> void BasicHashtable<F>::copy_buckets(char** top, char* end) {
zgu@13195 298 intptr_t len = _table_size * sizeof(HashtableBucket<F>);
duke@1 299 *(intptr_t*)(*top) = len;
duke@1 300 *top += sizeof(intptr_t);
duke@1 301
duke@1 302 *(intptr_t*)(*top) = _number_of_entries;
duke@1 303 *top += sizeof(intptr_t);
duke@1 304
duke@1 305 if (*top + len > end) {
coleenp@8076 306 report_out_of_shared_space(SharedMiscData);
duke@1 307 }
zgu@13195 308 _buckets = (HashtableBucket<F>*)memcpy(*top, _buckets, len);
duke@1 309 *top += len;
duke@1 310 }
duke@1 311
duke@1 312
duke@1 313 #ifndef PRODUCT
duke@1 314
zgu@13195 315 template <class T, MEMFLAGS F> void Hashtable<T, F>::print() {
duke@1 316 ResourceMark rm;
duke@1 317
zgu@13195 318 for (int i = 0; i < BasicHashtable<F>::table_size(); i++) {
zgu@13195 319 HashtableEntry<T, F>* entry = bucket(i);
duke@1 320 while(entry != NULL) {
duke@1 321 tty->print("%d : ", i);
duke@1 322 entry->literal()->print();
duke@1 323 tty->cr();
duke@1 324 entry = entry->next();
duke@1 325 }
duke@1 326 }
duke@1 327 }
duke@1 328
duke@1 329
zgu@13195 330 template <MEMFLAGS F> void BasicHashtable<F>::verify() {
duke@1 331 int count = 0;
duke@1 332 for (int i = 0; i < table_size(); i++) {
zgu@13195 333 for (BasicHashtableEntry<F>* p = bucket(i); p != NULL; p = p->next()) {
duke@1 334 ++count;
duke@1 335 }
duke@1 336 }
duke@1 337 assert(count == number_of_entries(), "number of hashtable entries incorrect");
duke@1 338 }
duke@1 339
duke@1 340
duke@1 341 #endif // PRODUCT
duke@1 342
duke@1 343 #ifdef ASSERT
duke@1 344
zgu@13195 345 template <MEMFLAGS F> void BasicHashtable<F>::verify_lookup_length(double load) {
duke@1 346 if ((double)_lookup_length / (double)_lookup_count > load * 2.0) {
duke@1 347 warning("Performance bug: SystemDictionary lookup_count=%d "
duke@1 348 "lookup_length=%d average=%lf load=%f",
duke@1 349 _lookup_count, _lookup_length,
duke@1 350 (double) _lookup_length / _lookup_count, load);
duke@1 351 }
duke@1 352 }
duke@1 353
duke@1 354 #endif
anoll@22921 355
anoll@22921 356
coleenp@8076 357 // Explicitly instantiate these types
mgerdin@26422 358 #if INCLUDE_ALL_GCS
mgerdin@26422 359 template class Hashtable<nmethod*, mtGC>;
mgerdin@26422 360 template class HashtableEntry<nmethod*, mtGC>;
mgerdin@26422 361 template class BasicHashtable<mtGC>;
mgerdin@26422 362 #endif
coleenp@13728 363 template class Hashtable<ConstantPool*, mtClass>;
mgerdin@26421 364 template class RehashableHashtable<Symbol*, mtSymbol>;
mgerdin@26421 365 template class RehashableHashtable<oopDesc*, mtSymbol>;
zgu@13195 366 template class Hashtable<Symbol*, mtSymbol>;
coleenp@13728 367 template class Hashtable<Klass*, mtClass>;
iklam@34257 368 template class Hashtable<InstanceKlass*, mtClass>;
zgu@13195 369 template class Hashtable<oop, mtClass>;
hseigel@20282 370 #if defined(SOLARIS) || defined(CHECK_UNHANDLED_OOPS)
zgu@13195 371 template class Hashtable<oop, mtSymbol>;
mgerdin@26421 372 template class RehashableHashtable<oop, mtSymbol>;
hseigel@20282 373 #endif // SOLARIS || CHECK_UNHANDLED_OOPS
zgu@13195 374 template class Hashtable<oopDesc*, mtSymbol>;
zgu@13195 375 template class Hashtable<Symbol*, mtClass>;
zgu@13195 376 template class HashtableEntry<Symbol*, mtSymbol>;
zgu@13195 377 template class HashtableEntry<Symbol*, mtClass>;
zgu@13195 378 template class HashtableEntry<oop, mtSymbol>;
zgu@13195 379 template class BasicHashtableEntry<mtSymbol>;
zgu@13195 380 template class BasicHashtableEntry<mtCode>;
zgu@13195 381 template class BasicHashtable<mtClass>;
iklam@34257 382 template class BasicHashtable<mtClassShared>;
zgu@13195 383 template class BasicHashtable<mtSymbol>;
zgu@13195 384 template class BasicHashtable<mtCode>;
zgu@13195 385 template class BasicHashtable<mtInternal>;
mgronlun@36384 386 #if INCLUDE_TRACE
mgronlun@36384 387 template class Hashtable<Symbol*, mtTracing>;
mgronlun@36384 388 template class HashtableEntry<Symbol*, mtTracing>;
mgronlun@36384 389 template class BasicHashtable<mtTracing>;
mgronlun@36384 390 #endif
kvn@30593 391 template class BasicHashtable<mtCompiler>;